Three-conductor plug.



M. B. RICHTER.

THREE CONDUCTOR PLUG.

qnrucmou FILEDOCT. n. nu

Pdtenmd Apr. 29,1919."

1 mm mm, 4

UNITED STATES PATENT OFFICE.

' rnnnn-connuc'ron. PLUG.

Specification of Letters Patent.

MOETEN BALTHAZAB- RICHTER, OF COPENHAGEN,

Patented Apr.29,1919.

Original application filed October 16, 1915, Seriul No. 56,302. Divided and this application filed October 17, W i V 1918i Serial Roi 251L655.

To all whom, it mag] concern:

Be it known that I,- Mourns BALTHAZAR' RICHTER, a subject 'otthe King ofDeniner'k, residing at Copenhagen, Denmark, have in 5 vented certain new and useful Improve ments in Three-GomluctorPlugs, of which the following-is a full and clear specification, illustrated in the annexed drawings;- The particular novel features arevlnore fully pointed out in the annexedclaims.

The contact p'lugsfused intelephone stu tions frequently have the-disadvantage that their composite elements tend'to get loosened in their relative positionstl1rough'theropeated action of the contact springs of the jacks with which. the plugs continually cooperate. I have alreadypr'oduced two-conductor plugs through pressing of celluloid in hotand plastic co'ndi'tion into the space between the outer tlibe' shaped cover and the central conductor to overcome this difficulty. The present" invention aims at 3 producing three-conductor plugs in thes'aine nmuner, In producing such plugs; which consist of an inner central conductor and two concentric" conductorswsurrounding' the some and insulated from thesam'e and insulated from each other, diiiicujltieshave been "found partly in maintaining'the parts in the correct relative position" during the introduction into the mold; in which'they are placed during the pressing in of the insulating n1aterial, and partly in preventing the change of this correct posi-tion of the parts under 85 theinfiuence of'the side pressure exercised by the lesti'ef eelluloid or other insu1ating mass which ispre'ssed in'througha single hole in. the side and which; should 'flow'ibetwen and :surrourtdthe inner arts, completely filling "oiit -all cavities; "wording to "the present invention, thisis "attained by 'the two inner" co'nfductorsbeing "secured to an auxiliary metal i'e'ce'preferably by using 'thes'ame screw ho esi'n the conductors which are later on used" "for attaching the flexible cords to themlf flhis metal piece,'together with" the three conductors'ofthe plug; placed a mold securing the concentric posi'tio'n of-the'p'artsund supporting the same, whereby the inetalgpicccin-question takes up'lth'e side pressure which is e'xertedby the plastic insulating material when itxis -pressed in through 'a hole in the outer conductor opposite totfemetal piece, 7

Theunethod i inanufstcturing this plug and claimed in a co has been described fine outer screw threads 9' be screwed against a shoulder i, and finally rial is to be forced. The inner hollow con- 5 I for onecoreo of the eordgand a hole 'n through which plasti v insulating material can be pressed. The central conductor conpending application, Serial #536,302, filed October 16, 1915 of which thepresent a plication is a division, claiming in particular; 1 the structure of this plug. do

The invention will now be described by way of example with reference to the an nexed drawing, in which- Figure "1 shows a-plug according to theinvention, the. outer cover of insulating material being shown in section;

Fig. 2 represents an axial longitudinal section through Fig. 1. i

Fig; 3 a sectional viewcof the outer conductor,

Fig. i the inner concentric hollow conduc ton,

Fig. 5 a sectional View of the same,

Fig. 6 the central conductor partially in section, i

Fig; 7 the knob -..:Eorming the outermost part ofthe plug in'section,

Fig 8n. metal ring fortaking up wear, Fig. 9 the contact plug partly in section prior to the pressing-in of insulating material, together with the devices used for keeping the various parts in the correct'mutual position, g 1

Fig. 10 the parts of the contact plug placed in a mold ready'for pressin in of the plastic insulating material, one elf of themold being removed, and p Fig. 11 a piece'of cord for use in connection with'the plug.

The outer conductor consists of a tube shaped cover a. It is provided with an excision b in th side and with acoarse internal screw thread 0' for screwing in of the cord f provided witha soft 'coatin d, (Fig; 11), one metal core 6 of which isien't over and thus "gets into contact with the cover a; Furthermore," the cover a is provided with (Figs 1 and 3) on which a tube h of insulating material can opposite to t e excision?) a conical opening j is proxuded in the wall of the cover a through which the plastic insulating mateductor is has the shape shown in Figs. {land 5 and ends in. ring-shaped part mean-t for makmg contact with one of the contact springs of a j sch; In the other end is found 'a' screw threaded hole m'for the fastening sists of a pin g, (Fig. 6), which is provided with a screw hole 19 on the end of which pin 9 the knob 1', shown in Fig. 7, can be screwed, which latter is adapted for makin contact with another contact spring of the ack, and a metal ring t, Fig. 8, is insulated from the parts 1' and k and serves for taking up the A ductor k, which is now introduced into the pressed against the left hand cover a from the left side. The pm 9 is'now introduced into the conductor is from the right side, and the knob 1 is screwed on subsequent to the ring t being applied, which .ring if has one fiber ring t and t on each side. A metal piece .90 (Fig. 9), the surface ofwhich is partly cylindrical and partly of the shown stepped shape is now applied and the parts I: and g are secured to the same by means of screws y which are screwed into the holes 11. and p which later on serve for receiving the fastening screws for the cores of the-cord. In a screw hole inv the end of the part m a thumb screw 2 is threaded, which has a shoulder abutting against the end of the cover a and thereby keeps the piece is and the ring o firmly end of the cover a. While this arrangement keeps the inner conductors exactly centered at one end, their other ends are centered by the position of the whole plug in the split twopart mold; one half of which is shown in Fig. 10 The mold is made of metal and has a suitable cav ity accommodating the entire device ,show 'yf in Fig. 9, the two halves being kepti'togetl'ur by bolts 1. The mold is further prot i'iifid with a cavity 2 of the shape shown, containing a piston 3 and insulating material 4 and terminating right opposite to the o ening j in the cover a. When the parts oi the plug are laid in and the mold is screwed together, a thumb screw 5v is screwed in, pressing the piece 1", the fiber rings and the ring t firmly against the part hand the other parts and taking up part. of the pressure exerted by the insulating mass which is afterward introduced under pressure. In order to make possible the independent setting of the part a, provision is made in part at for suflicient play of screw 3 a small free space being provided as shownat 6 in Fig. 9. When the parts are ut'together in this manner, the whole mold with contents is heated until the insulating material 4 has become soft and plastic, and through a strongpressure on the piston 3,

the .insulatin mass is driven in through the opening j, fil ing out all the spaces between the parts 1', a, w and the mold 7. 1 After cooling, the plug is taken out of the mold and the superfluous is out 01f.

The cover is at the end provided with small notches 8, Fig. 3, and the rin t is providedwith similar notches 9, an it is an indication that the plug is completely filled, when the insulating material pressed in, appears in and fills out the notches in question. The cord f can now be screwed in and the cores 0 and s are fastened by means of screws, whereupon the outer tube h of insulating material serving as a handle, is screwed on.

The plug shown is only to be considered part of the insulating- -mass as an example and various details can be terminals.

2. A multiple conductor lug comprisinga central conductor, a plura ity of rigid concentric hollow conductors, spaced from the central conductor and from each other by auxiliary insulating elements, and a main body of insulating material pressed, while in a plasticcondition, into the cavities between the several conductorsnot occupied by auxiliary insulating elements, said insulating material formln' an integral body throughout the plug anf uniting the several plugelements to form an integral rigid structure.

3. A multi le conductor lug comprising a central condhctor, a plura ity of rigid con centric hollow conductors, tubular auxiliary insulating elements between the several conductors and near one end thereof, a main body of insulating material pressed, while in a plastic condition, into the cavities between the several conductors not occupied by the tubular auxiliary insulating elements, said insulating material forming an integral body throughout the plug and uniting the conductors, auxiliary insulating elements and insulating material into an integral structure, and an outer insulating handling sleeve.

HORTEN BALTHAZAR mourns. 

